Uplink transmissions via a license assisted cell in a wireless network

ABSTRACT

A wireless device receives downlink control information comprising: an allocation of resource blocks for transmission of uplink data via a subframe of a LAA cell; a first field comprising an index indicating a starting position for the transmission of the uplink data, the index identifying one of pre-configured starting positions; and a second field indicating an ending symbol for the transmission of the uplink data, the ending symbol being one of pre-configured ending symbols. A listen-before-talk procedure indicating a clear channel is performed before the starting position of the subframe. Based at least on the starting position and the ending symbol, the uplink data to resource elements corresponding to the resource blocks are mapped. The uplink data is transmitted, via the LAA cell, starting at the starting position in the subframe and ending before the ending symbol.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.15/421,049, filed Jan. 31, 2017, which claims the benefit of U.S.Provisional Application No. 62/290,739, filed Feb. 3, 2016, which ishereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosureare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present disclosure.

FIG. 3 is an example diagram depicting OFDM radio resources as per anaspect of an embodiment of the present disclosure.

FIG. 4 is an example block diagram of a base station and a wirelessdevice as per an aspect of an embodiment of the present disclosure.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure.

FIG. 6 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure.

FIG. 10 is an example diagram depicting a downlink burst as per anaspect of an embodiment of the present disclosure.

FIG. 11 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 12 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 13 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 14 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 15 is an example diagram depicting timing advance as per an aspectof an embodiment of the present disclosure.

FIG. 16 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 17 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 18 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 19 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

FIG. 20 is an example diagram depicting signal transmission as per anaspect of an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present disclosure enable operation ofcarrier aggregation. Embodiments of the technology disclosed herein maybe employed in the technical field of multicarrier communicationsystems.

The following Acronyms are used throughout the present disclosure:

ASIC application-specific integrated circuit

BPSK binary phase shift keying

CA carrier aggregation

CSI channel state information

CDMA code division multiple access

CSS common search space

CPLD complex programmable logic devices

CC component carrier

DL downlink

DCI downlink control information

DC dual connectivity

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FPGA field programmable gate arrays

FDD frequency division multiplexing

HDL hardware description languages

HARQ hybrid automatic repeat request

IE information element

LAA licensed assisted access

LTE long term evolution

MCG master cell group

MeNB master evolved node B

MIB master information block

MAC media access control

MAC media access control

MME mobility management entity

NAS non-access stratum

OFDM orthogonal frequency division multiplexing

PDCP packet data convergence protocol

PDU packet data unit

PHY physical

PDCCH physical downlink control channel

PHICH physical HARQ indicator channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

PCell primary cell

PCell primary cell

PCC primary component carrier

PSCell primary secondary cell

pTAG primary timing advance group

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RBG Resource Block Groups

RLC radio link control

RRC radio resource control

RA random access

RB resource blocks

SCC secondary component carrier

SCell secondary cell

Scell secondary cells

SCG secondary cell group

SeNB secondary evolved node B

sTAGs secondary timing advance group

SDU service data unit

S-GW serving gateway

SRB signaling radio bearer

SC-OFDM single carrier-OFDM

SFN system frame number

SIB system information block

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TA timing advance

TAG timing advance group

TB transport block

UL uplink

UE user equipment

VHDL VHSIC hardware description language

Example embodiments of the disclosure may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure. As illustrated inthis example, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentdisclosure. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, the radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as 0.5 msec, 1 msec,2 msec, and 5 msec may also be supported. Subframe(s) may consist of twoor more slots (for example, slots 206 and 207). For the example of FDD,10 subframes may be available for downlink transmission and 10 subframesmay be available for uplink transmissions in each 10 ms interval. Uplinkand downlink transmissions may be separated in the frequency domain.Slot(s) may include a plurality of OFDM symbols 203. The number of OFDMsymbols 203 in a slot 206 may depend on the cyclic prefix length andsubcarrier spacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present disclosure. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or RBs (in this example 6 to 100 RBs) may depend,at least in part, on the downlink transmission bandwidth 306 configuredin the cell. The smallest radio resource unit may be called a resourceelement (e.g. 301). Resource elements may be grouped into resourceblocks (e.g. 302). Resource blocks may be grouped into larger radioresources called Resource Block Groups (RBG) (e.g. 303). The transmittedsignal in slot 206 may be described by one or several resource grids ofa plurality of subcarriers and a plurality of OFDM symbols. Resourceblocks may be used to describe the mapping of certain physical channelsto resource elements. Other pre-defined groupings of physical resourceelements may be implemented in the system depending on the radiotechnology. For example, 24 subcarriers may be grouped as a radio blockfor a duration of 5 msec. In an illustrative example, a resource blockmay correspond to one slot in the time domain and 180 kHz in thefrequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers).

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure. FIG. 5A shows an example uplink physicalchannel. The baseband signal representing the physical uplink sharedchannel may perform the following processes. These functions areillustrated as examples and it is anticipated that other mechanisms maybe implemented in various embodiments. The functions may comprisescrambling, modulation of scrambled bits to generate complex-valuedsymbols, mapping of the complex-valued modulation symbols onto one orseveral transmission layers, transform precoding to generatecomplex-valued symbols, precoding of the complex-valued symbols, mappingof precoded complex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present disclosure.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to aspects of an embodiments, transceiver(s) may be employed.A transceiver is a device that includes both a transmitter and receiver.Transceivers may be employed in devices such as wireless devices, basestations, relay nodes, and/or the like. Example embodiments for radiotechnology implemented in communication interface 402, 407 and wirelesslink 411 are illustrated are FIG. 1, FIG. 2, FIG. 3, FIG. 5, andassociated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to various aspects of an embodiment, an LTE network mayinclude a multitude of base stations, providing a user planePDCP/RLC/MAC/PHY and control plane (RRC) protocol terminations towardsthe wireless device. The base station(s) may be interconnected withother base station(s) (for example, interconnected employing an X2interface). Base stations may also be connected employing, for example,an S1 interface to an EPC. For example, base stations may beinterconnected to the MME employing the S1-MME interface and to the S-G)employing the S1-U interface. The S1 interface may support amany-to-many relation between MMEs/Serving Gateways and base stations. Abase station may include many sectors for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI), and at RRCconnection re-establishment/handover, one serving cell may provide thesecurity input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC), while in the uplink,the carrier corresponding to the PCell may be the Uplink PrimaryComponent Carrier (UL PCC). Depending on wireless device capabilities,Secondary Cells (SCells) may be configured to form together with thePCell a set of serving cells. In the downlink, the carrier correspondingto an SCell may be a Downlink Secondary Component Carrier (DL SCC),while in the uplink, it may be an Uplink Secondary Component Carrier (ULSCC). An SCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may apply,for example, to carrier activation. When the specification indicatesthat a first carrier is activated, the specification may also mean thatthe cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE release with agiven capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTEtechnology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand DC as per an aspect of an embodiment of the present disclosure.E-UTRAN may support Dual Connectivity (DC) operation whereby a multipleRX/TX UE in RRC CONNECTED may be configured to utilize radio resourcesprovided by two schedulers located in two eNBs connected via a non-idealbackhaul over the X2 interface. eNBs involved in DC for a certain UE mayassume two different roles: an eNB may either act as an MeNB or as anSeNB. In DC a UE may be connected to one MeNB and one SeNB. Mechanismsimplemented in DC may be extended to cover more than two eNBs. FIG. 7illustrates one example structure for the UE side MAC entities when aMaster Cell Group (MCG) and a Secondary Cell Group (SCG) are configured,and it may not restrict implementation. Media Broadcast MulticastService (MBMS) reception is not shown in this figure for simplicity.

In DC, the radio protocol architecture that a particular bearer uses maydepend on how the bearer is setup. Three alternatives may exist, an MCGbearer, an SCG bearer and a split bearer as shown in FIG. 6. RRC may belocated in MeNB and SRBs may be configured as a MCG bearer type and mayuse the radio resources of the MeNB. DC may also be described as havingat least one bearer configured to use radio resources provided by theSeNB. DC may or may not be configured/implemented in example embodimentsof the disclosure.

In the case of DC, the UE may be configured with two MAC entities: oneMAC entity for MeNB, and one MAC entity for SeNB. In DC, the configuredset of serving cells for a UE may comprise two subsets: the Master CellGroup (MCG) containing the serving cells of the MeNB, and the SecondaryCell Group (SCG) containing the serving cells of the SeNB. For a SCG,one or more of the following may be applied. At least one cell in theSCG may have a configured UL CC and one of them, named PSCell (or PCellof SCG, or sometimes called PCell), may be configured with PUCCHresources. When the SCG is configured, there may be at least one SCGbearer or one Split bearer. Upon detection of a physical layer problemor a random access problem on a PSCell, or the maximum number of RLCretransmissions has been reached associated with the SCG, or upondetection of an access problem on a PSCell during a SCG addition or aSCG change: a RRC connection re-establishment procedure may not betriggered, UL transmissions towards cells of the SCG may be stopped, anda MeNB may be informed by the UE of a SCG failure type. For splitbearer, the DL data transfer over the MeNB may be maintained. The RLC AMbearer may be configured for the split bearer. Like a PCell, a PSCellmay not be de-activated. A PSCell may be changed with a SCG change (forexample, with a security key change and a RACH procedure), and/orneither a direct bearer type change between a Split bearer and a SCGbearer nor simultaneous configuration of a SCG and a Split bearer may besupported.

With respect to the interaction between a MeNB and a SeNB, one or moreof the following principles may be applied. The MeNB may maintain theRRM measurement configuration of the UE and may, (for example, based onreceived measurement reports or traffic conditions or bearer types),decide to ask a SeNB to provide additional resources (serving cells) fora UE. Upon receiving a request from the MeNB, a SeNB may create acontainer that may result in the configuration of additional servingcells for the UE (or decide that it has no resource available to do so).For UE capability coordination, the MeNB may provide (part of) the ASconfiguration and the UE capabilities to the SeNB. The MeNB and the SeNBmay exchange information about a UE configuration by employing RRCcontainers (inter-node messages) carried in X2 messages. The SeNB mayinitiate a reconfiguration of its existing serving cells (for example, aPUCCH towards the SeNB). The SeNB may decide which cell is the PSCellwithin the SCG. The MeNB may not change the content of the RRCconfiguration provided by the SeNB. In the case of a SCG addition and aSCG SCell addition, the MeNB may provide the latest measurement resultsfor the SCG cell(s). Both a MeNB and a SeNB may know the SFN andsubframe offset of each other by OAM, (for example, for the purpose ofDRX alignment and identification of a measurement gap). In an example,when adding a new SCG SCell, dedicated RRC signaling may be used forsending required system information of the cell as for CA, except forthe SFN acquired from a MIB of the PSCell of a SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure. In Example 1, pTAG comprises aPCell, and an sTAG comprises SCell1. In Example 2, a pTAG comprises aPCell and SCell1, and an sTAG comprises SCell2 and SCell3. In Example 3,pTAG comprises PCell and SCell1, and an sTAG1 includes SCell2 andSCell3, and sTAG2 comprises SCell4. Up to four TAGs may be supported ina cell group (MCG or SCG) and other example TAG configurations may alsobe provided. In various examples in this disclosure, example mechanismsare described for a pTAG and an sTAG. Some of the example mechanisms maybe applied to configurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to an embodiment, initial timing alignment may be achievedthrough a random access procedure. This may involve a UE transmitting arandom access preamble and an eNB responding with an initial TA commandNTA (amount of timing advance) within a random access response window.The start of the random access preamble may be aligned with the start ofa corresponding uplink subframe at the UE assuming NTA=0. The eNB mayestimate the uplink timing from the random access preamble transmittedby the UE. The TA command may be derived by the eNB based on theestimation of the difference between the desired UL timing and theactual UL timing. The UE may determine the initial uplink transmissiontiming relative to the corresponding downlink of the sTAG on which thepreamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to variousaspects of an embodiment, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding (configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, (for example, at least one RRC reconfigurationmessage), may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of thepTAG. When an SCell is added/configured without a TAG index, the SCellmay be explicitly assigned to the pTAG. The PCell may not change its TAgroup and may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (for example, to establish, modify and/orrelease RBs, to perform handover, to setup, modify, and/or releasemeasurements, to add, modify, and/or release SCells). If the receivedRRC Connection Reconfiguration message includes the sCellToReleaseList,the UE may perform an SCell release. If the received RRC ConnectionReconfiguration message includes the sCellToAddModList, the UE mayperform SCell additions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH may only be transmitted onthe PCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/or if theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the disclosure may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. This mayrequire not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum may therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it may be beneficialthat more spectrum be made available for deploying macro cells as wellas small cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, may be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA may offer an alternative for operators to make use ofunlicensed spectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAmay utilize at least energy detection to determine the presence orabsence of other signals on a channel in order to determine if a channelis occupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs, time & frequency synchronizationof UEs, and/or the like.

In an example embodiment, a DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

An LBT procedure may be employed for fair and friendly coexistence ofLAA with other operators and technologies operating in an unlicensedspectrum. LBT procedures on a node attempting to transmit on a carrierin an unlicensed spectrum may require the node to perform a clearchannel assessment to determine if the channel is free for use. An LBTprocedure may involve at least energy detection to determine if thechannel is being used. For example, regulatory requirements in someregions, for example, in Europe, may specify an energy detectionthreshold such that if a node receives energy greater than thisthreshold, the node assumes that the channel is not free. While nodesmay follow such regulatory requirements, a node may optionally use alower threshold for energy detection than that specified by regulatoryrequirements. In an example, LAA may employ a mechanism to adaptivelychange the energy detection threshold. For example, LAA may employ amechanism to adaptively lower the energy detection threshold from anupper bound. Adaptation mechanism(s) may not preclude static orsemi-static setting of the threshold. In an example a Category 4 LBTmechanism or other type of LBT mechanisms may be implemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies, no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (for example, LBT withoutrandom back-off) may be implemented. The duration of time that thechannel is sensed to be idle before the transmitting entity transmitsmay be deterministic. In an example, Category 3 (for example, LBT withrandom back-off with a contention window of fixed size) may beimplemented. The LBT procedure may have the following procedure as oneof its components. The transmitting entity may draw a random number Nwithin a contention window. The size of the contention window may bespecified by the minimum and maximum value of N. The size of thecontention window may be fixed. The random number N may be employed inthe LBT procedure to determine the duration of time that the channel issensed to be idle before the transmitting entity transmits on thechannel. In an example, Category 4 (for example, LBT with randomback-off with a contention window of variable size) may be implemented.The transmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by a minimumand maximum value of N. The transmitting entity may vary the size of thecontention window when drawing the random number N. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle before the transmitting entitytransmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (for example, by using different LBT mechanismsor parameters), since the LAA UL may be based on scheduled access whichaffects a UE's channel contention opportunities. Other considerationsmotivating a different UL LBT scheme include, but are not limited to,multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. A UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, a UL transmission burst may be defined from a UEperspective. In an example, a UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

In an example embodiment, in an unlicensed cell, a downlink burst may bestarted in a subframe. When an eNB accesses the channel, the eNB maytransmit for a duration of one or more subframes. The duration maydepend on a maximum configured burst duration in an eNB, the dataavailable for transmission, and/or eNB scheduling algorithm. FIG. 10shows an example downlink burst in an unlicensed (e.g. licensed assistedaccess) cell. The maximum configured burst duration in the exampleembodiment may be configured in the eNB. An eNB may transmit the maximumconfigured burst duration to a UE employing an RRC configurationmessage.

The wireless device may receive from a base station at least one message(for example, an RRC) comprising configuration parameters of a pluralityof cells. The plurality of cells may comprise at least one license celland at least one unlicensed (for example, an LAA cell). Theconfiguration parameters of a cell may, for example, compriseconfiguration parameters for physical channels, (for example, a ePDCCH,PDSCH, PUSCH, PUCCH and/or the like).

In an example embodiment, an LAA cell may support uplink transmissionsby one or more UEs in a given subframe. Example embodiments providemechanisms for one or more UEs to transmit uplink signals when an eNBtransmits to the one or more UEs uplink DCI grant(s) to allocateresource blocks to the one or more UEs to transmit in the uplink in oneor more subframes. In an example, when more than one UE is scheduled totransmit in the uplink in one or more subframes of a cell, a UE'stransmission may not block another UE's LBT and/or transmission.Different UEs may be allocated different non-overlapping resourceblocks. In an example, different UEs may employ overlapping RBs usingMU-MIMO.

An eNB may transmit at least one RRC message to one or more UEs toconfigure one or more LAA cells, LBT parameters and/or uplinktransmission parameters. One or more configuration parameters may beconfigured by one or more RRC messages. Example configuration parametersare one or more LBT configuration parameters, and/or data/control signaltransmission parameters. For example, one or more parameters of an LBTthreshold may configured by an eNB. Example embodiments enhances LAAcell configuration and allows an eNB to semi-statically configure LBTparameters that control a wireless access procedure to an LAA cell.

An eNB may transmit uplink DCI grants to the one or more UEs for anuplink transmission on one or more LAA cells. To enable transmissions bymultiple users in a subframe of an LAA cell, some form ofLBT/transmission grouping may be implemented. The LBT mechanism mayenable transmission from one or more UEs within a group. In an example,transmission from a UE may not block LBT and/or transmission of anotherUE in that group.

One or more UEs may be directed by an eNB to start performing an LBTprocedure. The eNB may transmit one or more DCIs to one or more UEs. Theone or more DCIs may indicate one or more configuration parameters suchas the LBT starting time in a subframe, a reservation signal startingtime, an allowed starting time for uplink data/control signaltransmission in a subframe, and/or transmit power control parameters. AneNB may transmit to one or more UEs one or more (e)PDCCH DCIs causingconfiguration of one or more uplink transmission configurationparameters. Some of the configuration parameters may be coordinated(e.g. be the same) for one or more UEs within a group (e.g. LBT startingtime, reservation signal starting time, and/or allowed starting time foruplink data/control signal transmission). For example, the eNB maytransmit one or more DCIs indicating the same starting time for the LBT,the same reservation signal transmission timing, and/or the samedata/control signal transmission timing by UEs in a group. There may bemultiple implementation options for grouping multiple UEs.

In an example, an eNB may transmit to a first UE a first DCI comprisinga first RBs allocation, transmission starting time, and/or LBT type(e.g. timing). The eNB may transmit to a second UE a second DCIcomprising a second RBs allocation, with a same transmission startingtime and/or LBT type (e.g. timing). When MU-MIMO is not used for thefirst and second UE, the first RBs allocation may not overlap with thesecond RBs allocation. When the first UE and second UE are configuredfor MU-MIMO, the first RBs allocation may be the same as the second RBsallocation.

In an example implementation, one or more RRC messages may comprise oneor more configuration parameters for LBT grouping. UEs within a cell maybe grouped through RRC configuration. An eNB may schedule UL resourcesfor one or more UEs within a group and may coordinate their LBT timeand/or procedure. UEs failing LBT within a time window may need to waitfor the next allowed timeslot to perform LBT if scheduled again by theeNB. Multiple UEs in a group may perform LBT and may transmit at thesame time. In an example configuration, the configuration of LBT starttimes may be coordinated and staggered across neighboring eNBs toincrease probability of LBT success.

In an example implementation, dynamic LBT grouping based on schedulingmay be implemented (e.g. without explicit RRC grouping configuration).Grouping of UEs for LBT may be implemented by the eNB scheduler. The eNBmay schedule one or more UEs in the same subframe n. Multiple UEsscheduled for UL transmission on subframe n may start LBT substantiallyat a same time/symbol in a subframe. The scheduler may transmit uplinkgrant to one or more UEs. The one or more UEs receiving uplink grant forthe same subframe, may start LBT at a specific starting time in thesubframe. The one or more UEs receiving uplink grant for the samesubframe, may start transmission of uplink reservation signal at aspecific starting time in a subframe. The one or more UEs receivinguplink grant for the same subframe, may start transmission of uplinkdata signals at a specific starting time in a subframe. The coordinationamong one or more UEs grouped to transmit uplink data signals in thesame subframe may be based on PDCCH uplink grants.

In an example, an eNB may transmit (e)PDCCH DCIs to one or more UEs in afirst subframe and instruct one or more UEs to start an LBT processstarting from a starting point in a second subframe. In an example, aneNB may transmit (e)PDCCH DCIs to one or more UEs in a first subframeand instruct one or more UEs to start uplink transmission from astarting point in a second subframe after the corresponding LBTsucceeds. One or more UEs are directed by an eNB to start LBT may bescheduled to transmit in the same subframe. In this case LBT andtransmission timing may be designed to enable users within a group notblock each others LBT.

In an example, possible LBT starting time may be preconfigured and/orsignaled to the UE, e.g. a first symbol/starting-time for UEs in agroup. In an example, possible uplink transmission starting time may bepreconfigured and/or signaled to the UE, e.g. a firstsymbol/starting-time for UEs in a group. If one or more UEs fail the LBTprocess during a period, the one or more UEs may not start a new LBTprocess until the one or more UEs receive further indication from theeNB, e.g. with a new uplink grant. In an example, one or more UEs whichpass the LBT earlier than other UEs in the group may not transmit untilthe LBT period is over may transmit at an uplink transmission startingtime. In an example, one or more UEs detecting a clear channel via theLBT process may start uplink transmission. The UEs may transmit areservation signal until beginning of a permissible PUSCH transmissiontime, e.g. start of subframe n, start of a symbol, start of the secondslot, etc.

In an example, the reservation signal from UE1 may not block LBT ofother UE's in the same group and may be intended to block othersUEs/other nodes (e.g. WiFi nodes) not in a group from acquiring thechannel till UL data transmission starts. The reservation signal may bea wideband signal and may block other UEs/other nodes (e.g. WiFi nodes)from grabbing the channel. In an example, UEs in a group may senddifferent reservation signals based on some UE specificconfigurations/codes such that eNB can detect who has passed the LBT. Inan example, reservation signal may be one of or a combination of one ofthe following: arbitrary noise-like signal to keep the channel, DM-RS asconfigured by eNB, a sequence of SRS signals as configured by eNB,and/or a PRACH with a preamble configure by eNB.

In an example embodiment, one or more UEs may be configured not totransmit a reservation signal before transmitting uplink data. In anexample embodiment, the possible starting symbols of the uplink datatransmission in a subframe may be preconfigured (e.g. by RRC signalingor by implementation). In an example embodiment, the UE may be allowedto transmit at one or more starting symbols in a subframe. The UE maystart transmission of uplink data at a permitted starting symboldepending on when LBT process indicate a clear channel.

FIG. 11, shows an example uplink transmission for UE1 and UE2 on an LAAcell.

In an example implementation, variable LBT period (e.g. 50 micro second,longer than one symbol, etc) may be implemented. An eNB may indicate astarting symbol for LBT to one or more UEs (e.g. in the same group). AneNB may indicate a starting symbol for uplink transmission to one ormore UEs (e.g. in the same group). If LBT fails during the first period(e.g. a first symbol), the UE may try LBT on next duration (e.g. nextsymbols) and may transmit data/reservation signals in UL when LBT passeswithin configured LBT window considering a maximum LBT duration period.UL data transmission may start at an allowed starting time within ascheduled subframe n. UE's which pass LBT before starting time within ascheduled subframe n may send a reservation signal till the beginningstarting symbol in subframe n. For example, a UE scheduled for subframen may start LBT up to L symbols (or L micro seconds) before startingtime of subframe n and if LBT fails on first duration (e.g. symbol) butpasses on second duration (e.g. symbol), the UE may send a reservationsignal following LBT success and until the start of an uplink datatransmission time.

In an example, some UEs within a group may be performing LBT procedurewhile others already succeeded and are transmitting reservation signalsand/or data signals. In an example, the reservation signal and/or datasignals from one member of a group may not block LBT of other members ofthe same group but may block other users/nodes (e.g. WiFi nodes) in theband until transmission of data on scheduled subframe n. In an exampleimplementation, a UE may derive the configuration of a sub-bandreservation signal from allocated physical RBs.

FIG. 12, shows an example uplink transmission for UE1 and UE2 on an LAAcell. UE1 and UE2 access the channel at different times.

In an LAA cell, uplink transmission timing is advanced by N_TA as shownin FIG. 15. A UE advances its transmission timing based on TACs receivedfrom the eNB, e.g. to compensate for round-trip propagation delay. Thismay imply that from a UE transmitter uplink subframe timing starts andends earlier than downlink subframes. A guard period is needed whendownlink transmission ends and uplink transmission starts in a UE. TheeNB may not be able to calculate the exact N_TA amount, since the UE mayautonomously change the N_TA in some scenarios. The guard period isrequired so that uplink and downlink transmission timings do not overlapin a TDD system.

In an example embodiment, the guard period may provide a transmissiongap. Other UEs/nodes (e.g. Wifi nodes) may acquire the channel afterdownlink transmission ends, and during the transmission gap. This maynot allow a UE to acquire the channel and transmit uplink data if the UEis granted an uplink resource after a downlink burst. For example,transmission of reservation signals by a UE may enable to reserve thechannel earlier and subsequently transmit uplink data.

In an LAA system, when an eNB transmits a full downlink subframe, thenext available subframe for uplink transmission may be a partial uplinksubframe due to transmission gap and NTA requirements. In an LAA system,when an eNB transmits an end partial downlink subframe, the nextavailable subframe for uplink transmission may be a full or partialuplink subframe due to transmission gap and NTA requirements.

An eNB may need to schedule an uplink transmission on a last subframe ofan uplink burst that ends before the last symbol of a subframe, forexample ends at the end of the first slot of the uplink subframe, or atsymbol 10, 12, 13, etc.

In an example, an uplink DCI grant may include explicit indication thatthe grant is for a partial subframe. An eNB may transmit to a UE anuplink DCI grant comprising an allocation of resource blocks fortransmission of uplink data in a first subframe of an LAA cell. Theuplink DCI grant may further comprise a first field comprising an indexindicating a starting position (time). The starting position (time) isone of a plurality of pre-configured allowed starting positions (times).The uplink DCI grant may further comprise a second field indicating anending symbol. The ending symbol is one of a plurality of pre-configuredallowed ending symbols. The index may identify an allowed startingsymbol/time of a plurality of starting symbols/times for transmission ofuplink signals (data/reservation signals). For example, an RRC messagemay comprise (and configure) one or more allowed starting symbols/timesidentified by indexes and/or allowed ending symbols identified byindexes. The starting time may be for a reservation signal and/or fordata transmission.

Example embodiment reduces uplink DCI grant size and reduces downlinksignaling overhead. An index identifies one of the pre-configuredallowed starting positions. Using an index and limiting the number ofpossible starting positions reduces the number of bits for the firstfield in the DCI. For example, a 2-bit index may indicate four startingpositions. Also reducing the allowed ending symbol positions reduces thenumber of bits for encoding the second field. Example embodiments reducethe required number of bits in the first field and the second field andenhances downlink control channel capacity.

The wireless device may perform, on the LAA cell and before the startingposition of the first subframe, an LBT procedure employing the LBTconfiguration parameters. The wireless device may start uplinktransmission after the LBT procedure indicates a clear channel. A UE mayprepare uplink data format and map uplink data to physical resourcesbased, at least, on specific partial uplink subframe configurationindicated in the uplink DCI grant. The UE may map the uplink data toresource elements corresponding to the resource blocks allocated fortransmission and based, at least, on the starting position and theending symbol. The UE may map the physical uplink shared channel toresource elements of allocated resource blocks. For example, when uplinkdata channel starts from symbol 1, the UE may not map the uplink data tosymbol 0. For example, when uplink data channel does not include thelast symbol, the UE may not map the uplink data to the last symbol ofthe first subframe. The UE may transmit the uplink data on the LAA cellstarting at the starting position and ending before the ending symbol.The UE may transmit a reservation signal when the channel is clear untilthe allowed symbol (time) to send data/PUSCH. The UE may start uplinkdata transmission at the allowed starting symbol.

Example embodiments enhances uplink data mapping to resource elements.Instead of puncturing uplink data for a partial subframe, uplink data ismapped to resource elements based on the starting and ending symbolpositions. A UE may calculate the size of the uplink resources inadvance and accordingly construct a data packet (Transport block) forthe allocated resources. Example embodiments may reduce the probabilityof packet loss and retransmissions and may enhance uplink radio resourceefficiency.

In an example embodiment, the downlink transmission from an eNB on anLAA cell may end with a downlink partial subframe. In this case toincrease transmission efficiency, a UE may start UL transmission shortlyafter the end point of a DL partial subframe. To enable uplink datatransmission after an end partial downlink subframe or a full downlinksubframe, an eNB may indicate support for such uplink transmissions andmay configure a set of available starting points for a beginning uplinkpartial subframes. Such configuration may be cell specific or UEspecific.

In an example embodiment, one or more UEs may be scheduled to starttransmission of uplink data on an uplink partial subframe. A limitednumber of starting points may be configured for a UE. In an example,beginning partial subframes may be based on uplink part of one or moreof TDD special subframe configurations. In another example, otherconfigurations for partial beginning uplink subframe may be configured.For example, in a system in which a subframe includes 14 symbols, an eNBmay allow uplink data to be transmitted starting on symbols 4, 7, or 10of a subframe. In an example, the UE behavior depends on whether Uplinkreservation signal transmission is enabled in the uplink or not.

In an example embodiment, transmission of a UE reservation signal may beenabled. When downlink transmission ends on symbol x of a subframe, UEsscheduled to transmit after the end partial/full downlink subframe, maystart LBT after k duration (for example, k=0, 20 micro seconds, 50micro-seconds, 1 symbols, or 2 symbol, etc). The UE may transmit areservation signal when the channel is clear until a permissible symbol(time) to send data/PUSCH. The UE may start uplink data transmission ata permissible symbol.

For example, if duration of LBT plus reservation signal is fixed, e.g.one symbol LBT and no reservation signal, the eNB may know the startingtime and mapping of data may prepare to receive the uplink dataaccordingly. The eNB may employ the uplink reference signal to determinewhen the uplink subframe started and/or ended.

In an example embodiment, the starting symbol of UL data in an endingpartial downlink subframe may be preconfigured. In an exampleembodiment, when subframe n is a partial end downlink subframe, a UE maystart LBT and then transmit reservation signals until the beginning ofsubframe n+1 (e.g. uplink grant from the eNB may be for subframe n+1).This may happen for example when no allowable starting symbol isavailable in subframe n after LBT is successful. This may happen forexample, when subframe n is the ending partial subframe, and the eNB maytransmit a grant for subframe n+1. An eNB may know when the endingdownlink partial subframe n ends. The eNB may transmit DCI grants forsubframe n or n+1 depending on the ending time. FIG. 13 illustrates LBTprocedure and uplink transmission on subframe comprising a partial DLsubframe.

In an example embodiment, an eNB may transmit reservation signals in oneor more subsequent symbols after the ending downlink partial subframe toreserve the channel and not allow other unwanted UEs or nodes (e.g. WiFinodes) to acquire the channel. This may depend on eNB implementation aswell as maximum transmission time allowed by the eNB. The eNB may not beable to send terminal reservation signals when the maximum downlinktransmission duration is reached.

In an example embodiment, transmission of UE reservation signal may notbe enabled. In this case UEs scheduled to transmit in UL on subframe nwhen downlink part ends on symbol x, may wait until an earliest allowedpermissible start time (symbol) for uplink data transmission. UEs mayrun LBT during a time interval before transmitting data on symbol y. Inan example, the eNB may transmit a reservation signal to reserve thechannel for the UE before the UE starts an LBT process. Example LBTdurations are in term of symbols, in an implementation LBT duration maybe in terms of micro seconds, e.g. 30, 40, 50 micro seconds. Exampleembodiments may be implemented according to the configured LBT process.FIG. 14 illustrates LBT procedure and uplink transmission on a subframecomprising a partial DL subframe.

According to various embodiments, a device such as, for example, awireless device, a base station and/or the like, may comprise one ormore processors and memory. The memory may store instructions that, whenexecuted by the one or more processors, cause the device to perform aseries of actions. Embodiments of example actions are illustrated in theaccompanying figures and specification.

FIG. 16 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1610, a wireless device may receive one ormore radio resource control (RRC) messages. The at least one RRC messagemay comprise configuration parameters for a first licensed assistedaccess (LAA) cell. The one or more configuration parameters may compriseone or more listen before talk (LBT) configuration parameters. Adownlink control information (DCI) may be received at 1620. The DCI maycomprise: an allocation of resource blocks for transmission of uplinkdata in a subframe, an index indicating a starting position for theuplink data in the subframe, and a field indicating an ending symbol forthe uplink data. The index may identify one of a plurality ofpre-configured starting positions. The ending symbol may be one of aplurality of pre-configured ending symbols. At 1630, the wireless devicemay perform, on the LAA cell and before the starting position of thesubframe, an LBT procedure employing the one or more LBT configurationparameters. The LBT procedure may indicate a clear channel. At 1640, thewireless device may map the uplink data to resource elementscorresponding to the resource blocks allocated for transmission andbased, at least, on the starting position and the ending symbol. At1650, the wireless device may transmit the uplink data on the LAA cellstarting at the starting position in the subframe and ending before theending symbol.

The subframe may be, for example, a starting subframe of amulti-subframe burst. According to an embodiment, the transmitting ofthe uplink data may comprise: transmitting a reservation signal until anallowed symbol for a physical uplink shared channel transmission, andtransmitting data symbols starting from the allowed symbol. Thereservation signal duration may be, for example, less than one symbol.The starting position may be, for example, based on a value of an uplinktiming advance calculated by the wireless device. The DCI may comprise,for example, an LBT parameter. The DCI may comprise, for example, atransmit power control (TPC) command. The configuration parameters maycomprise, for example, uplink transmission parameters. The DCI mayindicate, for example, a starting time for the LBT procedure. A startingtime for the LBT procedure may be at, for example, a pre-determined timebefore the starting position.

FIG. 17 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1710, a wireless device may receive one ormore DCI. The one or more DCI(s) may comprise: an allocation of resourceblocks for transmission of uplink data in a subframe of a licensedassisted access (LAA) cell, an index indicating a starting position forthe uplink data in the subframe, and a field indicating an ending symbolfor the uplink data. The index may identify one of a plurality ofpre-configured starting positions. The ending symbol may be one of aplurality of pre-configured ending symbols. At 1720, the wireless devicemay perform an LBT procedure on the LAA cell. The LBT procedure mayindicate a clear channel. At 1730, the wireless device may map theuplink data to resource elements corresponding to the resource blocksallocated for transmission and based, at least, on the starting positionand the ending symbol. At 1740, the wireless device may transmit, theuplink data on the LAA cell, starting at the starting position in thesubframe and ending before the ending symbol.

FIG. 18 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1810, a wireless device may receive one ormore DCI. The one or more DCI(s) may comprise: an allocation of resourceblocks for transmission of uplink data in a subframe of a licensedassisted access (LAA) cell, an index indicating a starting position forthe uplink data in the subframe, and a field indicating an ending symbolfor the uplink data. The index may identify one of a plurality ofpre-configured starting positions. The ending symbol may be one of aplurality of pre-configured ending symbols. At 1820, the wireless devicemay perform an LBT procedure on the LAA cell. The LBT procedure mayindicate a clear channel. At 1830, the wireless device may transmit, theuplink data on the LAA cell, starting at the starting position in thesubframe and ending before the ending symbol.

FIG. 19 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1910, a wireless device may receive one ormore DCI. The one or more DCI(s) may comprise: an allocation of resourceblocks for transmission of uplink data in a subframe of a licensedassisted access (LAA) cell, an index indicating a starting position forthe uplink data in the subframe, and a field indicating an ending symbolfor the uplink data. The index may identify one of a plurality ofpre-configured starting positions. The ending symbol may be one of aplurality of pre-configured ending symbols. At 1920, the wireless devicemay transmit, the uplink data on the LAA cell, starting at the startingposition in the subframe and ending before the ending symbol.

FIG. 20 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 2010, a base station may transmit one or moreDCI. The one or more DCI may comprise: an allocation of resource blocksfor transmission of uplink data in a subframe of a licensed assistedaccess (LAA) cell, an index indicating a starting position for theuplink data in the subframe, and a field indicating an ending symbol forthe uplink data. The index may identify one of a plurality ofpre-configured starting positions. The ending symbol may be one of aplurality of pre-configured ending symbols. At 2020, the base stationmay receive, the uplink data on the LAA cell, starting at the startingposition in the subframe and ending before the ending symbol.

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example.” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {ce111}, {cell2}, and {cell1, cell2}.

In this specification, parameters (Information elements: IEs) maycomprise one or more objects, and each of those objects may comprise oneor more other objects. For example, if parameter (IE) N comprisesparameter (IE) M, and parameter (IE) M comprises parameter (IE) K, andparameter (IE) K comprises parameter (information element) J, then, forexample, N comprises K, and N comprises J. In an example embodiment,when one or more messages comprise a plurality of parameters, it impliesthat a parameter in the plurality of parameters is in at least one ofthe one or more messages, but does not have to be in each of the one ormore messages.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e. hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLabVIEWMathScript. Additionally, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers and microprocessors are programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDsare often programmed using hardware description languages (HDL) such asVHSIC hardware description language (VHDL) or Verilog that configureconnections between internal hardware modules with lesser functionalityon a programmable device. Finally, it needs to be emphasized that theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using FDD communication systems. However, one skilled in the art willrecognize that embodiments of the disclosure may also be implemented ina system comprising one or more TDD cells (e.g. frame structure 2 and/orframe structure 3-licensed assisted access). The disclosed methods andsystems may be implemented in wireless or wireline systems. The featuresof various embodiments presented in this disclosure may be combined. Oneor many features (method or system) of one embodiment may be implementedin other embodiments. Only a limited number of example combinations areshown to indicate to one skilled in the art the possibility of featuresthat may be combined in various embodiments to create enhancedtransmission and reception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

1. A method comprising: receiving, by a wireless device, a downlinkcontrol information comprising: an allocation of resource blocks fortransmission of uplink data via a subframe of a licensed assisted access(LAA) cell; a first field comprising an index indicating a startingposition for the transmission of the uplink data, the index identifyingone of pre-configured starting positions; and a second field indicatingan ending symbol for the transmission of the uplink data, the endingsymbol being one of pre-configured ending symbols; performing, beforethe starting position of the subframe, a listen-before-talk procedureindicating a clear channel; mapping, based at least on the startingposition and the ending symbol, the uplink data to resource elementscorresponding to the resource blocks; and transmitting, the uplink datavia the LAA cell, starting at the starting position in the subframe andending before the ending symbol.
 2. The method of claim 1, wherein thesubframe is a starting subframe of a multi-subframe burst.
 3. The methodof claim 1, wherein the transmitting the uplink data further comprises:transmitting a reservation signal until an allowed symbol for a physicaluplink shared channel transmission; and transmitting data symbolsstarting from the allowed symbol.
 4. The method of claim 3, wherein aduration of the reservation signal is less than one symbol.
 5. Themethod of claim 1, wherein the starting position is based on a value ofan uplink timing advance calculated by a wireless device.
 6. The methodof claim 1, wherein the downlink control information comprises alisten-before-talk parameter.
 7. The method of claim 1, wherein thedownlink control information comprises a transmit power control command.8. The method of claim 1, further comprising receiving uplinktransmission parameters for the LAA cell.
 9. The method of claim 1,wherein the downlink control information indicates a starting time forthe listen-before-talk procedure.
 10. The method of claim 1, wherein astarting time for the listen-before-talk procedure is at apre-determined time before the starting position.
 11. A wireless devicecomprising: one or more processors; and memory storing instructionsthat, when executed by the one or more processors, cause the wirelessdevice to: receive a downlink control information comprising: anallocation of resource blocks for transmission of uplink data via asubframe of a licensed assisted access (LAA) cell; a first fieldcomprising an index indicating a starting position for the transmissionof the uplink data, the index identifying one of pre-configured startingpositions; and a second field indicating an ending symbol for thetransmission of the uplink data, the ending symbol being one ofpre-configured ending symbols; perform, before the starting position ofthe subframe, a listen-before-talk procedure indicating a clear channel;map, based at least on the starting position and the ending symbol, theuplink data to resource elements corresponding to the resource blocks;and transmit, the uplink data via the LAA cell, starting at the startingposition in the subframe and ending before the ending symbol.
 12. Thewireless device of claim 11, wherein the subframe is a starting subframeof a multi-subframe burst.
 13. The wireless device of claim 11, whereinthe instructions, when transmitting the uplink data, further cause thewireless device to: transmit a reservation signal until a first allowedsymbol for a physical uplink shared channel transmission; and transmitdata symbols starting from the first allowed symbol.
 14. The wirelessdevice of claim 13, wherein a duration of the reservation signal is lessthan one symbol.
 15. The wireless device of claim 11, wherein thestarting position is based on a value of an uplink timing advancecalculated by the wireless device.
 16. The wireless device of claim 11,wherein the downlink control information comprises a listen-before-talkparameter.
 17. The wireless device of claim 11, wherein the downlinkcontrol information comprises a transmit power control command.
 18. Thewireless device of claim 11, wherein configuration parameters for theLAA cell comprise uplink transmission parameters.
 19. The wirelessdevice of claim 11, wherein the downlink control information indicates astarting time for the listen-before-talk procedure.
 20. The wirelessdevice of claim 11, wherein a starting time for the listen-before-talkprocedure is at a pre-determined time before the starting position.